Stereoselective Synthesis of Tetrasubstituted Alkenes via a Cp*Co -Catalyzed C-H Alkenylation/Directing Group Migration Sequence.

A highly atom economical and stereoselective synthesis of tetrasubstituted α,β-unsaturated amides was achieved by a Cp*Co -catalyzed C-H alkenylation/directing group migration sequence. A carbamoyl directing group, which is typically removed after C-H functionalization, worked as an internal acylating agent and migrated onto the alkene moiety of the product. The directing group migration was realized with the Cp*Co catalyst, while a related Cp*Rh catalyst did not promote the migration process. The product was further converted into two types of tricyclic compounds, one of which had fluorescent properties.